Chemical process



Patented June 25, 1946 CHEMICAL PROCESS Mark w. Farlow and Wilbur A.Lazler,

assignors to E. I. du Pont de Nemours ton, Del.,

Wilming- & Company, Wilmington, DeL, a corporation of Delaware NoDrawing. Application January 22,1941, Serial No. 375,458

41 Claims. 1

This invention relates to the manufacture of amides of undecylenic acidand is directed to new and useful processes in which an amine is reactedwith an amide-forming ricinoleic compound to form an amide, and theamide is pyrolyzed to yield the corresponding amide of undecylenic acidand other products. Still more particularly, this invention relates tothe manufacture of N-isobutylundecylenamide by the pyrolysis ofN-isobutylricinoleamide.

The manufacture of N-isobutylundecylenamide hasheretofore been dependentupon the separate manufacture of undecylenic acid. The most common, ifnot the only practical method of producing undecylenic acid is fromcastor oil or other esters of ricinoleic acid. Formerly it was thusproduced as a by-product in the manufacture of heptaldehyde. Theundecylenic acid thus obtained is of poor quality and the yields arelow. Careful purification is required, especially if an acid suitablefor manufacturing N -isobutylundecylenamide is to be obtained. This,coupled.

with the careful purification which needs to be effected in isolatingN-isobutylundecylenamide from the products of the amidation reaction,makes for an undesirably complicated and expensive manufacturingprocess.

It has now been found that N -isobutylundecylenamide and other amides ofundecylenic acid are obtainable in high yields and at low cost byamidating castor oil or like amide-forming ricinoleic compounds withisobutylamine or other amines (inclusive of ammonia), and pyrolyzing theresulting amides. It has been found that when N-isobutylricinoleamide,whether separated, partially separated, or unseparated from the otherproducts of amidation of castor oil with isobutylamine, is subjected topyrolysis, N-isobutylundecylenamide is formed as the dominant productand can be separated by fractionation in high yields and of a puritysuitable for use in fiy sprays, as set forth in U. S. Patents 2,166,119and 2,166,120.

The amidation may be carried out in any of a number of ways, thepreferred method being to react castor oil with isobutylamine undersuitable amidating conditions. The reaction takes place slowly at roomtemperature, and if time is not a factor it is sufficient merely to mixthe two reagents and to allow the mixture to stand in any suitablecontainer several weeks prior to use. A preferred method, however, is tocarry out the reaction at a higher temperature in a pressure vessel asillustrated in the following example, in which the parts are by weightunless otherwise specified.

Example 1 Thirty-one parts of castor oil and 9 parts of isobutylamineare charged: into a pressure vessel of such dimensions that on heatingto 165 C. a pressure of to lbs. per square inch is obtained. Afterheating at C. for 16 hours, there is obtained an ahnost whiteVaselinelike solid melting at about 30 C. This product is washed withseveral portions of hot water, then dissolved in ether and washed withdilute hydrochloric acid until free from amine. The ether solution isthen dried over anhydrous sodium sulfate and evaporated in. vacuo,leaving 30 parts of a product analyzing 3.7% nitrogen.

Another preferred method is to mix castor oil and isobutylamine inappropriate quantities with a small quantity of a low-boiling inertliquid and to heat the mixture under reflux until no further temperaturerise occurs in the liquid phase. In this manner, the reactiontemperature may be regulated according to the nature and the amount ofthe inert liquid employed, and the progress of the reaction may beobserved by the change in the temperature of the liquid phase underreflux. Two modifications of this method are illustrated by Examples 2and 3.

Example 2 Fourteen parts of castor oil and 5 parts of isobutylamine areplaced in .a reaction vessel and heated under reflux at atmosphericpressure with stirring for 12 hours. The excess isobutylamine and theglycerol formed in the reaction are removed by distillation at 2 mm.pressure. The distillation is continued until the temperature of thevapor reaches 160 C. and there is obtained as residue 16 parts of aproduct having an iodine number of 73ml (calculated forN-isobutyh'icinoleamide, 71.9) and a nitrogen content of 3.9%(calculated, 1%). y

In this modification, the excess of isobutylamine functions not only toaid in the completion of the reaction but also as the low-boiling inertliquid which governs the final temperature of reflux.

Example 3 A mixture of 2796 parts of castor oil, 657 parts ofisobutylamine and 100 parts of toluene is placed in a reaction vesseland heated at atmospheric pressure under reflux until the rate oftemperature rise in the liquid phase is small, or until titration ofunreacted isobutylamine indicates that the desired degree of amidationhas been attained. In a typical operation, the temperature of the liquidrose gradually as follows: 1 hour, 96 0.; 5.5 hours, 150 C; 9.2 hours,163 0.; 12.3 hours, 0.; 16.3 hours, 174 C.; 17.8 hours, 175 C. After aheating period of 18 hours, titration of a portion of the mixture withstandard hydrochloric acid, using methyl red as the indicator, showedthe presence of only 5% of the isobutylamine originally present, or 'anamidation of 95%.

In place of the toluene other low-boiling solvents may be employed. Asalready mentioned, an excess of isobutylamine serves this function inthe modification of Example 2. Preferably, however, the solvent is notwater-miscible to any great extent so that glycerol and any unreactedamine may be washed out with water without removing the solvent.

The purpose of the low-boiling solvent is primarily to control the finaltemperature of reflux. Additionally, it aids in washing out glycerol andany unreacted amine. It also has beneficial functions in the pyrolysis,as will be pointed out hereinafter. The nature and character of thesolvent is determined largely by its primary function. Thus it should beinert, it should have a low enough boiling point, and should be used insufflcient quantity to keep the final temperature of reflux within thedesired limits. It should not be so low-boiling or used in such largequantities, however, that the temperature of reflux becomes too low.Preferably, it should have a boiling point at atmospheric pressurebetween about 50 C. and 250 C. and should be used in sufficientquantities to provide an initial temperature of reflux above about 50 C.and a final temperature of reflux below about 300 C.

The N-isobutylamide of ricinoleic acid prepared by any suitableamidation process (such as any one of those outlined above) is subjectedto pyrolysis to yield the N-isobutylamide of undecylenic acid, probablyaccording to the following equations:

unreacted components of the castor oil. While' such crude products maybe pyrolyzed directly to produce the N-isobutylamide of undecylenicacid, it is of advantage first to recover the glycerol, not only toavoid loss of this valuable product but also to avoid contamination ofthe N-isobutylamide of undecylenic acid with its products of pyrolysis.Glycerol undergoes dehydration to form the very reactive aldehyde,acrolein. When this product is present during the pyrolysis, undesirableside reactions reduce yields of the desired amide and cause theformation of tar-like substances which are difficult to separate bydistillation. Other constituents of the crude amidation product may beremoved, if desired, even to the extent of isolating the N-isobutylamide of ricinoleic acid in a relatively pure form, oralternatively a more pure product may be obtained by starting with purerraw materials.

The pyrolysis of the N-isobutylamide of recinoleic acid may be carriedout under atmospheric, sub-atmospheric or superatmospheric pressure, andaccording to the temperature and pressure chosen may be carried outeither in the vapor or liquid phase. It is usually accomplished bypassing the vapor or liquid, or mixture of vapor and liquid, with orwithout a diluent; through a cracking tube maintained at crackingtemperatures. In a. preferred method, the product to be cracked isextended by means of a diluent which may be a liquid, a vapor, or a gasaccording to whether the cracking is carried out in the vapor or liquidphase. Such diluents aid in the mechanical operations involved inhandling the amidation product, and in case of vapor phase processes aidin adjusting the partial pressure of the amide vapors. A volatilethermally stable solvent for the amides such as toluene is a suitablediluent. In the liquid phase process the volatility of the solvent aidsin its recovery and separation from the products of pyrolysis, and inthe vapor phase process the volatile solvent facilitates thevaporization of the high-boiling amides involved.

Various modifications of the invention are illustrated in the followingexamples, in which the parts are by weight unless otherwise specified.The percentage yields are based upon parts of ricinoleic acid for each100 parts of castor oil. The percentage of ricinoleic acid combined incastor oil varies from about '75 to about parts per parts of the oil.

Example 4 The amidation product of Example 2 was taken up in 3920 partsof toluene and washed with warm water, the water layer being separatedand set aside. The toluene solution thus prepared is introduced dropwiseat the rate of 1'15 parts per hour into the top of a cracking tubeconsisting of a steel pipe having an internal diameter of 1.50 inchesand a length of 40 inches, mounted vertically and packed over a-lengthof 26 inches with solid steel spheres having a diameter of 0.3735 inch.The cracking tube is surrounded by an electric furnace and thetemperature in the cracking zone is maintained at 490 to 500 C. by

means of automatic controllers actuated by athermocouple embedded in thewalls of the tube at a point approximately midway along the heatedlength.

From the lower end of the cracking tube, the product is conductedthrough a water-cooled condenser into a suitable receiver and fittedwith means for disposing of gaseous products which are formed in smallamounts. The condensed product is transferred to a fractionating stillhaving an efliciency of twenty theoretical plates, and separated intothe following fractions, in which the parts are by weight per 100 partsof original solution:

Substance B. P. O./m1n. pressure Part9 Toluene 55. 0 Heptaldehyde 54-5825 2. 4 Middle cut 7. 4 N-isobutylundecylenamide... 21. 0 Residue 3,1

The crude product prepared by refluxing 2796 parts of castor oil with723 parts of isobutylamine for twenty hours, followed by dilution with1400 parts of methanol, is fed at the rate of 92 parts per hour into anapparatus arranged similarly to that of Example-4 except that thecracking tube is of Pyrex glass packed with 8-mm. lengths oi 8-mm. Pyrexglass tubing. The cracking zone is maintained at 500 C.

The product is worked up as described in Example 4 and givesN-isobutylundecylenamide and heptaldehyde in yields of '74 and 35%,respectively, of the theoretical.

Example 6 A toluene solution of' the amidation products of castor olland isobutylamine prepared as described in Example 4 is pumped at therate of 1140 parts per hour through a cracking unit maintained at 475 C.under a pressure of 1000 to 1200 lbs. per sq. inch, the pressure beinginitially established in the apparatus by means of nitrogen. Thecracking unit consists of a hellcally wound tube embedded in acylindrical solid aluminum casting. The helix is prepared from a 6-footlength of inch 0. D. by inch I. D.

' chrome-nickel (18-8) stainless steel tubing emgether with a smallamount of heptaldehyde.

tube and a receiver connected through a water- 1 cooled condenser withthe top f the cracking tube. The receiver is provided with a pressuregauge and a valve so that the unit can be operated at the desiredpressure. During the run described, the tendency toward a rise inpressure is counteracted by releasing nitrogen, or, when this isexhausted, the liquid or gaseous product from the receiver as required.

N-isobutylundecylenamide is isolated from the product in a yield of 74%of the theoretical.

Example 7 The method of Example 6 is repeated at 450 C. i

and a pressure of 2000 to 2200 lbs. per sq. inch. The yield ofN-isobutylundecylenamide is 66% of the theoretical.

Example 8 glycerol and excess isobutylamine, as described in Example 4,is cracked at the rate of 90 parts per hour at 500 C. and at atmosphericpressure.

N-iso'butylundecylenamide and heptaldehyde are isolated from the productin yields of 78 and 48%, respectively, of the theoretical.

Example 9 Isobutylamides, prepared and freed of glycerol and excessisobutylamine as described in Example 2, are vaporized and passeddownward through a Example 10 A mixture of 190 partsof castor oil and44.6 parts of isobutylamine is heated in a closed pressure vessel at 175C. until titrationof a. test portion with standard hydrochloric acid andmethyl red indicator shows the presence of no more than 4 to 5% of freeamine. The crude product is discharged into a settling tank, 104 partsof toluene and 320 parts of water are added, the mixture is warmed toabout 80C., agitated, and finally allowed to settle into two layers. Thelower layer is drawn on and discarded while the oil layer is vaporizedat a rate of 3500 cc. per hour and passed downward through a verticallymounted, stainless steel pipe having an internal diameter of 1.6 inchesand a length of 30 inches, maintained at 500 C. and atatmosphericpressure, The product iscondensed and fractionally distilledas in Example 4, giving N -isobutylundecylenamide ina yield of 80% ofthe theoretical, 1

' halidemay be reacted with ammonia or any suitable aliphatic oraromatic amine, e. g., ethyl, propyl, amyl, octyl, dodecyl, hexadecyl,and cyclohexyl amines, piperidine, alpha-aminopyridine, aniline, etc.,and the resulting amide of ricinoleic acid subjected to pyrolysis toyield the corresponding amide of undecyclenic acid.

Variations likewise maybe made in the details of the cracking processesand, as indicated in the examples, a wide range of conditions of temperature, pressure and space velocity in the cracking zone may obtain.Although the proper interrelation of these variables is important in thepractical and economical operation of the invention, they are not socritical as to make their precise determination necessary to thesuccessful practice of the invention. By an examination of the examplesherein. set forth, one can select a set of conditions applicable to theapparatus at hand. For example, if production of gaseous or low-boilingliquid products is excessive, the cracking convertically mountedstainless steel tube having an internal diameter of 1.6 inches and alength of 30 inches at the rate of 3,000 cc. per hour at 500 C. and atatmospheric pressure. The cracked material is led through a water-cooledcondenser into a receiver. The crude condensate is worked up as inExample 4, giving N-isobutylundecylenditions are too severe and the useof lower temperatures or shorter times of contact or a combination ofboth is indicated.

In general, it will be found that best results are obtained within atemperature range of about 400 to 550 C. and at pressures up to, about3000 lbs, per sq. inch. Within these ranges of temperatures andpressures, the pyrolysis may be effected simply by adjusting the spacevelocity to the optimum yield of undecylenamide. If desired, however,the process may be operated at subatmospheric pressures.

Though with a given apparatus greater capacity is obtained at higherpressures, it is generally more desirable to operate at lower. pressuresnot only for mechanical reasons but because higher yields ofundecylenamide are obtainable. It is preferable to operate underconditions of temperature and pressure such that the cracking takesplace in the vapor phase. Although the line of demarcation between vaporphase and liquid phase processes is not always apparent, in genera], theadvantages of vapor phase operation are more likely to be obtained atpressures less than about 100 lbs. per sq. inch.

Other variations in the details of the cracking processes, particularlywith reference to the nature of the diluent, may be made. Thus, in placeof the toluene and methanol illustrated there may be substituted otherthermally stable volatile solvents for the amides. Volatile aromatichydrocarbons or their alkyl substitution products are preferred, such asbenzene, toluene, the xylenes, amyl benzenes, and the like. Othersolvents, however, such as methanol,,cyclohexane, diethyl ether,kerosene or gasoline and the like may be used. Any solvent which isthermally stableand inert. to the essential reactants and products maybe used. The diluent function of the solvent may also be obtained whollyor in part by means of an inert carrier gas such as nitrogen, carbondioxide, dimethyl ether, and the like.

The quantity of diluent may be varied widely without deleteriouslyafiecting the operations. Preferably, however, it is used in suchquantities that the fluid undergoing cracking does not contain more thanabout 90% or the amidation product. In other words, aboutlO to 50% ofthe fluid should be made up of the diluent. In case the diluent is asolvent for the amide, it should be used in suflicient amount to providea free-flowing and easily handled solution, especially if a vapor phasecracking process is involved. In such a case, solutions containing from50 to 90% of the amidation product are most suitable.

While the amidation and pyrolysis processes have been illustrated asseparate, steps, it is possible to carry out the two reactionssimultaneously. Thus, a solution of castor oil or other amide-formingricinoleic compound and isobutylamine, or other amine, in toluene orother solvent may be fed directly into the cracking zone andN-lsobutylundecyleneamide isolated from the reaction product. In suchcases, however, because the rates of amidation and pyrolysis are not thesame it is sometimes desirable to provide suitable difierentials intemperature and space velocity. Thus, with apparatus similar to thatdescribed in Example 6 two temperature zones may be maintained, oneoptimum for amidation and the other optimum fOr cracking. Thesemodifications are most suitably carried out at high pressures as inExamples 6 and 7, since the amidation proceeds more rapidly under theinfluence of temperature and pressure. In such modifications it may bedesirable to use simple esters of ricinoleic acid such as the methylester or the acid itself, or its anhydride, instead of castor oil andthus avoid having the reaction product contaminated with glyceroldecomposition products.

Since many apparently widely differing embodiments of the invention maybe made, it is to be understood that such variations as come within thespirit of the invention are intended to be included.

We claim:

1. In the manufacture of the N-isobutylamide oi undecylenic acid, themethod which comprises reacting castor oil with isobutylamine to formthe N-isobutylamide of ricinoleic acid, diluting the amide thus formedwith an inert substantially water-insoluble solvent therefor, washingwith water to-remove glycerol and unreacted isobutylamine, vaporizingsaid amide and said solvent and subjecting said amide in admixture withthe vapors or said solvent to pyrolysis to form heptaldehyde and theN-isobutylamide of undecylenic acid and isolating the amide thus formed.

2. In the manufacture or the N-isobutylamide oi undecylenic acid, themethod which comprises reacting castor oil with isobutylamine atatmospheric pressure and under reflux in the presence of an inert,substantially water-insoluble, liquid soluble in the reaction mixture,said liquid boiling substantially at a temperature 0: 50 C. to 250 C.and being present in an amount suflicient to provide a final temperatureof reflux in the liquid phase not substantially in excess of 300 C.,diluting the reaction mixture with an additional quantity of saidliquid, washing with water to remove glycerol and unreactedisobutylamine, subjecting the washed product to pyrolysis to formheptaldehyde and the N-lsobutylamide of undecylenic acid and isolatingthe amide thus formed.

3. In the manufacture of amides of ricinoleic acid, the method whichcomprises reacting castor oil with isobutylamine under reflux and atatmospheric pressure in the presence of an inert, substantiallywater-insoluble, liquid soluble in the reaction mixture, said liquidboiling substantially at a temperature of 50 C. to 250 C. and beingpresent in an amount sufllclent to provide a flnal temperature of refluxin the liquid phase not substantially in excess of 300 C., diluting theproduct with a further quantity of said liquid sufllcient to provide afluid product when cooled, and washing it with water to remove glyceroland any unreacted is'obutylamine.

4. Th method which comprises reacting castor oil with isobutylamineunder reflux and at atmospheric pressure in the presence of an inertsubstantially water-insoluble liquid soluble in the reaction mixture,said liquid boiling substantially at a temperature of 50 C. to 250 C.and bein present in an amount such that the final temperature of refluxin the liquid phase does not substantially exceed 300 C. I

5. The method which comprises reacting castor oil with isobutylamineunder reflux and at atmospheric pressure in the presence of an inertsubstantially water-insoluble liquid soluble in the reaction mixture,said liquid boiling substantially at a temperature of 50 C. to 250 C.and being resent in an amount such that the final temperature of refluxin the liquid phase does not substantially exceed 300 0., adding afurther quantity of said liquid sufficient to produce a fluid productwhen cooled, and washing it with water to remove glycerol and anyunreacted isobutylamine.

6. In the manufacture of amides of undecylenic acid the method whichcomprises amidating castor oil to form an amide of ricinoleic acid, re-

moving glycerol, dissolving the amide of ricinoleic acid in an inertsolvent, subjecting said solution t pyrolysis to form heptaldehyde andthe amide 9 the corresponding amide of undecylenic acid andheptaldehyde.

8. In the manufacture of amides of undecylenic acid, the method whichcomprises subjecting an amide of ricinoleic acid to pyrolysissubstantially at a temperature of 400 C. to 550 C. and while the partialpressure of the amide is substantially less than atmospheric pressure.

9. In the manufacture of amides of undecylenic acid, the method whichcomprises subjecting an amide of ricinoleic acid to pyrolysissubstantially at a temperature of 400 C. to 550 C. while the amide is inthe vapor state and in admixture with a gaseous diluent. y

10. In the manufacture of amides of undecylenic acid, the method whichcomprises vaporizing an amide of ricinoleic acid and subjecting thevapor in admixture with a gaseous diluent to pyrolysis substantially ata temperature of 400 C. to 550 C.

11. In the manufacture of amides of undecylenic acid. the method whichcomprises vaporizing a solution of an amide of ricinoleic acid in athermally stable liquid hydrocarbon and heating the vapors substantiallyat a temperature of 400 C. to 550 C.

12. In the manufacture of amides of undecylenic acid, the method whichcomprises subJect-,

lenic acid, the method which comprises subjecting an amide of ricinoleicacid to pyrolysis substantially at a temperature of 400 C. to 550 C. toform the corresponding amide of undecylenic acid and heptaldehyde andisolating the amide thus formed.

15. In the manufacture of amides of undecylenic acid, the method whichcomprises subjecting an amide of ricinoleic acid to pyrolysissubstantially at a temperature of 400 C. to 550 C. and at a pressuresuch that the boiling point of the amide of ricinoleic acid is below itsdecomposition temperature.

16. In the manufacture of the N-isobutylamide of undecylenic acid, themethod which comprises reacting castor oil with isobutylamine to formthe N-isobutylamide of ricinoleic acid, diluting the amide thus formedwith an inert substantially water-insoluble solvent therefor boilingsubstantially at a temperature of 50 C. to 250 C., washing with water toremove glycerol and unreacted isobutylamine, vaporizing said amide andsubjecting it in admixture with the vapors of said solvent to pyrolysisto form heptaldehyde and the N-isobutylamide of undecylenic acid andisolating the amide thus formed.

17. In the manufacture of the N-isobutylamide of undecylenic acid, themethod which comprises reacting castor oil with isobutylamine to formthe N-isobutylamide of ricinoleic acid, diluting the amide thus formedwith an inert substantially water-insoluble solvent therefor .boilingsubstantially at a temperature of 50 C. to 250 C. in an amountsufiicient to provide a final temperature of reflux in the liquid-phasenot substantially in 18. In the manufacture of the N-isobutylamide ofundecylenic acid. the method which comprises reacting castor oil withisobutylamine at atmospheric pressure and under reflux in the presenceof a volatile aromatic hydrocarbon solvent, boiling substantially at atemp rature of 50 C. to 250 C., in an amount sufllcient to provide afinal temperature of reflux in the liquid phase notsubstantially inexcess of 300 C., diluting the reaction mixture with an additionalquantity of saidsolvent, washing with water to removeglycerol andunreacted isobutylamine, subjecting the washed product to pyrolysis toform heptaldehyde and the N-isobutylamide of undecylenic acid andisolating the amide thus formed.

19. In the manufacture of amides of ricinoleic acid, the method whichcomprises reacting castor oil with isobutylamine under reflux and atatmospheric pressure in the presence of a-volatile aromatic hydrocarbonsolvent, boiling substantially at a temperature of 50 C. to 250 C., inan amount sumcient to provide a final temperature of reflux in theliquid phase not substantially in excess of 300 C., diluting the productwith a further quantity of said solvent sufficient to provide a fluidproduct when cooled, and washing it with water to remove glycerol andany unreacted isobutylamine.

20. The method which comprises reacting castor oil with isobutylamineunder reflux and at atmospheric pressure in the presence of a volatilearomatic hydrocarbon solvent, boiling substantially at a temperature of50 C. to 250 in an amount such that the final temperature of reflux inthe liquid phase does not substantially exceed 300 C. 21. The methodwhich comprises reacting castor oil with isobutylamine under reflux andat atmospheric pressure in the presence of a volatile aromatichydrocarbon solvent, boiling substantially at a temperature of 50 C. to250 C.,in an amount such that the final temperature of reflux in theliquid phase does not substantially exceed 300 C., adding a furtherquantity of said solvent sumcient to produce a fluid product whencooled, and washing it with water to remove glycerol and any unreactedisobutylamine.

22. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises amidating castor oil to form the isobutylamide ofricinoleic acid, removing glycerol, dissolving the isobutylamide ofricinoleic acid in an inert solvent, subjecting said solution topyrolysis to form heptaldehyde and the isobutylamide of undecylenic acidand isolating the amide thus formed,

23. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises to 550 C. and while the partial Pressure of the"isobutylamide of ricinoleic acid is substantially less than atmosphericpressure.

25. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises subjecting the isobutylamide of ricinoleic acidto pyrolysis substantially at a temperature of 400 C. to 550 C. whilethe isobutylamide of ricinoleic acid is in the vapor state and inadmixture with a gaseous diluent.

26. In the manufacture of the isobutylamide of undecylenic acid. themethod which comprises vaporizing the isobutylamide of ricinoleic acidand subjecting the vapor-in admixture with a gaseous diluent topyrolysis substantially at a temperature of 400 C. to 550 C.

27. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises vaporizing a solution of the isobutylamide ofricinoleic acid in a thermally stable liquid hydrocarbon and heating thevapors substantially at a temperature of 400 C. to 550 C.

28. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises subjecting the isobutylamide of ricinoleic acidto pyrolysis substantially at a temperature of 400 C. to 550 C. andsubstantially at a pressure between 100 and 3000 lbs. per square inch,

29. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises subjecting a solution of the isobutylamide ofricinoleic acid in an inert solvent to pyrolysis substantially at atemperature of 400 C. to 550 C. and at a pressure sufficient to preventsubstantial vaporization of the isobutylamide oi. ricinoleic acid.

30. In the manufacture of the isobutylamide of undecylenic acid, themethodwhich comprises subjecting the isobutylamide of ricinoleic acid topyrolysis substantially at a temperature of 400 C. to 550 C. to form theisobutylamide of undecylenic acid and heptaldehyde and isolating theisobutylamide thus formed.

31. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises subjecting the isobutylamide of ricinoleic acidto pyrolysis substantially at a temperature of 400 C. to 550 C. and at apressure such that the boiling point of the isobutylamide of ricinoleicacid is below its decomposition temperature.

32. In the manufacture of the N-isobutylamide of undecylenic acid, themethod which comprises reacting castor oil with isobutylamine to formthe N-isobutylamide of ricinoleic acid, diluting the amide thus formedwith toluene, washing with water to remove glycerol and unreactedisobutylamine, vaporizing said amide and subjecting it in admixture withthe vapors of toluene to pyrolysis to form heptaldehyde and theN-isobutylamide of undecylenic acid and isolating the amide thus formed.

33. In the manufacture of the N-isobutylamide' of undecylenic acid, themethod which comprises reacting castor oil with isobutylamine atatmospheric pressure and under reflux in the presence of toluene in anamount sufficient to provid a final temperature of reflux in the liquidphase not substantially in excess of 300 C., diluting the reactionmixture with an additional quantity of toluene, washing with water toremove glycerol and unreacted isobutylamine, subjecting the washedproduct to pyrolysis to form heptaldehyde and the N-isobutylamide ofundecylenic acid and isolating the amide thus formed.

34. In the manufacture of amides of ricinoleic acid, the method whichcomprises reacting castor oil with isobutylamine under reflux and atatmospheric pressure in the presence of toluene in an amount suflicientto provide a flnal temperature of reflux in the liquid phase notsubstantially in excess of 300 C., diluting the product with a furtherquantity of toluene sufficient to provide a fluid product when cooled,and washing it with water to remove glycerol and any unreactedisobutylamine.

35. The method which comprises reacting castor oil with isobutylamineunder reflux and at atmospheric pressure in the presence of toluene inan amount such that the final temperature of reflux in the liquid phasedoes not substantially exceed 300 C.

36. The method which comprises reacting castor oil with isobutylamineunder reflux and at atmospheric pressure in the presence of toluene inan amount such that the final temperature of reflux in the liquid ph'asedoes not substantially exceed 300 0., adding a further quantity oftoluene sufficient to produce a fluid product when cooled, and washingit with water to remove glycerol and any unreacted isobutylamine.

' 37. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises amidating castor oil to form the isobutylamide ofricinoleic acid, removing glycerol, dissolving the isobutylamide ofricinoleic acid in toulene, subjecting said solution to pyrolysis toform h'eptaldehyde and the isobutylamide of undecylenic acid andisolating the amide thus formed.

38. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises preparing a solution of an amide of ricinoleicacid in toluene, vaporizing the solution and heating the vapors of theisobutylamide of ricinoleic acid while in admixture with the vapors oftoluene to a temperature of 400 C. to 550 C. to form the isobutylamideof undecylenic acid and heptaldehyde.

39. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises subjecting the isobutylamide of ricinoleic acidto pyrolysis substantially at a temperature of 400 C. to 550 C. whilethe isobutylamide of ricinoleic acid is in the vapor state and inadmixture with vapor of toluene.

40. In the manufacture of the isobutylamide of undecylenic acid, themethod which comprises vaporizing the isobutylamide of ricinoleic acidand subjecting the vapor in admixture with vapor of toluene to pyrolysissubstantially at a temundecylenic acid, the method which comprises

